Delivery and transfer mechanism



d 1935- I A. SWENSON 2,006,490

DELIVERY AND TRANSFER MECHANISM Filed Jan. 24, 1954 6 Sheets-Sheet 1 INVENTOR AL B/N SWE/VSON Y r 1 July 2,- 1935. A. SWENSON 2,006,490

DELIVERY AND TRANSFER MECHANISM Filed Jan. 24, 1954 s Sheets-Sheet 2 -INVENTOR: ALB/N SWENS N y ,1 A. SWENSON 2,006,490

DELIVERY AND TRANSFER MECHANISM Filed Jan. 24, 1954 6 Sheets-Sheet 3 A TORNEY zmsm 1::

jufiy '2, 1935. A. SWENSON DELIVERY AND TRANSFER MECHANISM Filed Jan. 24, 1934 6 Sheets-Sheet 4 .INVENTOR fiORNEY E x fir w W 6 fiufi 2, 1935. sw so I 2,006,490

DELIVERY AND TRANSFER MECHANISM Filed Jan. 24, 1954 '6 Sheets-Sheet 5 J06 SWE 501V 104 T ORNEY Patented July 2, 1935.

UNITED STATES-PATENT OFFICE f I 2,006,490 p sameness TRANSFER MECHANISM ime Swenson, New York, Y. i 7 Application January 24, 1934, Serial No. 708.019

12 Claims. (cram- 95.)

The present invention relates to apparatus for transferring from one level to another selected level, merchandise in the form'of bottles of milk, packages of food, and the like; and, particularly to a dumb-waiter'where the basement level serves as a station at which the bottles or packages are placed in the dumb-waiter car, the said car then being raised to an upper selected level at which time mechanism is brought into play to transfer said bottles or packages to receiving means at that level. I 7

At present, and as particularly pertaining to the delivery of milk in bottles, which delivery takes place during the night, the milk man must load a tray which he then carries with him to the doors of the various homes or apartments where he deposits upon the determined number of bottles. As especially-relating to delivery in apartment houses, he is often required to make many trips back to the vehicle from which he fillshis tray, and having to'walk, as is often the case, many steps of stairs, considerable time is lost in making his deliveries. Also having to set the bottles upon the floor, which-is not in every case clean, and'leaving them exposed to possible theft, the delivery of milk, as

at present constituted, has, in addition to the faults here mentioned, several others which need not be mentioned here.

The present invention, the provision of means preferably in the form of a dumb-waiter whereby milk or the like may be deposited from one station to receiving means contiguous to the apartment to which such delivery is to be made.

The invention also contemplates means, whereby the number of articles or bottles desired by the occupant of the apartment may be read by the person making the delivery, on an indicator or by 'means of signal lights or the like. v More specifically, the inventon has for its major object, the provision of a dumb-waiter having .a car movable from one level to a 'selected'upper 1evel,'said car having removable means receptive of an article such as a bottle of milk, and means at each of the other levels to receive the said car carried means, the dumb-waiteralso being provided with means to transfer the car. carried means from'the, car tothe receiving means at the selected'level.

Another object of the invention is to provide means carried bygthe car, which are'operable by the dumb-waiter shaft to effect the transfer of floor the previously therefore, contemplates the article receiving means from the car to the receiving means at a selected upper level.

A still furtherobject resides of pre-settable means whereby, plural'transfer means in each in the provision in the event of car, one or. more of said transfer means is operated simultaneously.

The foregoing and many other objects of the invention will be more clearly apparent from the the waiter constructedin accordance following detailed specification,descriptive of the drawings, which illustrate preinvention and, in

, elevation, a dumbwith the present inventionand in which a loading level and one receiving level are shown.

Fig. 2 is a side elevation of waiter shaft being shown in the same, the dumbsection.

Fig. 3 is aplan view of an. enlarged scale of the mechanism at .the bottom of the dumb-waiter shaft for driving the transfermeans carried .by.

the car.

Fig. 4 is a front view of the mechanism shown .in Fig. 3, the front bracket of which has been removed for the purpose of clarity.

Fig. 5 is a side elevational of the mechanism shown in view of that portion Figs. 3 and 4, which forms the final driving means for the car carried mechanism.

.Fig. 6 is an elevational view of that side of the car which carries the intermediate apparatus, and which is moved by the mechanism illustrated in Figs. 3, Land 5 for finally .means.

Fig.7? is a rear view of the Fig. 8 is a view similar. to

moving the transfer Fig. 6 but with the parts moved after transferhas taken place.

Fig. 9 is a plan section'of at one of the receiving levels.

Fig. 10 is a fragmentary plan detail of the car I transfer means. Fig. '11 is a front anism shown in Figs. 10 and Fig. 13 is a plan sectional the car as stationed I elevational view of the same. Fig. 12 is a rear elevational view of themechview similar to Fig.

10, and showing the transfer means at the completion of one-half of its cycle.

Fig. 14 is atop plan View of the car showing the means ultimately driven from the parts shown in Fig. 6 and finally driving th in Figsli).

-Fig5'15 is a fragmentary 7 'means shown in Fig. 14, and mechanism preferably located at the bottom of Fig. 16 is: an elevational showninFig.

e mechanism shown plandetail of the .QQ m, of a collar 57'. .largernent there may be positioned. a gear 58 Figs. 17 and 18 are fragmentary plan details of the car transfer means shown in Figs. 10-13 inclusive and drawn to enlarged scale. Figs. 19, 20 and 21 are fragmentary plan details of the means shown in Figs. 14, 15 and 16 and drawn to an enlarged scale and showing the parts in various positions during their movements.

Referring to the drawings in greater detail, the shaftway is shown at 20, and is provided with guides 2| for the car 22. The loading level is indicated at 23,' and an upper or transferring level at 24. Though only one such transfer level has been illustrated, it is readily apparent that the apparatus may be constructed to serve two or more such levels. The car 22 is counterweighted as at 23', and connections are made from the counterweight to the bottom of the car as at 24', and from the counterweight to the top of the car as at 25. The latter connection, maybe in the form of a cable or rope trained about sheave 25 located at the top or head of the shaft and the former is preferably in the form of a chain.

. As here illustrated, the car may be raised and lowered. by means of a handle or. crank 21, and through meansof the sprocket 28 and chain 29 a drive is effected to the sprocket 38, the shaft 3|, the gearing 32, and the shaft 33. Upon the latter shaft, there is mounted a sprocket'34 about which the lower "bight of the chain 24' is trained. To compensate for possible stretch in the chain 24 or the. cable 25, means such as the pivoted cross arms 35, is provided at the connection between the counter-weight 23 and the cable 25. One end .of each of these arms is pivotally connected tothe counterweight andthe other ends, each connected to a wire or cable'36 having a cross-head portion ili bElOWilihG counterweight. The upper end of the chain 24.is connected to the center of the .crossi-head. In this manner, slack due to stretch is taken up in the chain 24 and cable.25, so that 'thes'car will always have a definite position in relation to its driving means. a

The shaft .32 has keyed thereon, a drum 38 which atone face is provided with a threaded projection 39 adapted to engage a screw seat in a. fixed frame bracket 48. The drum 38 is prefer- :ably provided on its periphery with a recess 4| Eadapted to be. entered by a. pin 42 on the end of the arm 43. The arm 43 is mounted to rock iwith'or aroundv the stub shaft 44 and another curved arm 45 is arranged to move with the arm .43 in the mannerof a bell crank. This arm 45 is-preferably provided. with a lug 46 engageable in a cam notch 41 of a disc 48. This disc on one face-may also beprovided with a pin 49 adapted tojengage' against a portion of an over-standing finger. .50qformed on the arm 45. .The, disc 48 is preferably carried on a rock shaft 5| having means such as the hand wheel 52, whereby it may be manually manipulated. A cross shaft 53 may be driven from. the shaft 5| .bymeans such as a gearing 54. One end of the .shaft53, which'is supported in the brackets 55 and 56, is provided with an enlargement in the To one side of the said enfreely mounted on the shaft 53, and on the other side-of the enlargement there may be similarly .rnounted another gear 59, The gear 58 carries apawl 69: adapted to engage a notch 8| in the en; largement 51, and is provided with an outstand; ing tail portion, 52 anda somewhat similar but shorter head portion' 63, The bracket 51 maybe provided 'with'respective-stops Bland 55 for the mentioned tail portion 62 and head portipn '83,

The gear 59 is preferably provided with the pawl 66 similar to the pawl 60, the tail portion 61 and the head portion 68 which are adapted to respectively cooperate with stops 69 and 18, carried by the bracket 56. A notch H in staggered relation with the notch 6| is provided on the enlargement 57 for the pawl 66. The gear 58 is arranged to mesh with a rack 12 which is also provided with teeth 13 engageable. with mutilated pinions l4 and 75. These pinions are provided with central bores through which may slide the respective vertical racks l6 and 11. These racks are also keyed to their respective pinions so that rotation of the pinions will rotate the racks 1S and 11 also permitting Vertical movement of the said racks through the bores of the pinions by means of rotation of the gear-59. v

The racks 16 and 11 at their upper ends, are respectively provided with extensions in the form of the reds l8 a d 1 The ero e t to the full height of; the shaftwayand may bejo'urnaled at th ir up e nd in m a s Su h s b ac 8. Th r d 18 prefe abl p ov d with rmger-like' roiccti n 8.! and. he rod 79 is Similarly provided,.withtheprojection 82 for each upper level of the shaftway.

The car 22f is provided with means which may be engaged by these projections 8|. and 82 for transmitting the reciprocatory motion of the racks 16, 11 to the transfer mechanism. One manner for accomplishing this is best illustrated in Figs. 6, '7 and 8, and includes brackets 83 and 8.4.. adaptedto Slide ve t eally against the side of the car. The bracket 83 which is adapted to be movedby the finger 8| and the bracket 84 similarly movable. by the finger 8 2, are each provided at their upper and lower ends with outstanding lug portions85. The lower lugs 85 serving as anchoring meansfor opposite ends of a'cable or rope 9.6 abou a; pu l 81 rotatably mounted on, the side of the car. The upper ends 85 of the brackets 83 84 are each respectively connectedto cables 88, 89 bent around pulleys -90, 9| ,,and then fixedly anchored to a flange of a pulley. 92 loosely mounted at the top of the car.

The bracketfllt s p vid d w t a Me 9 a p d to enga e the to a e o t afi a r 8 h a finger is moved upwardly and similarly the bracket, is provided with a lug 94 engageable by the lower face of thefinger 82 when it is moved downwardly. The bracket 83 is also provided with a pivotedspring tensioned arm 95 having an abutting face. 96 for the lower face of the finger 8| and a similar spring tensioned arm 91 having an abutting face 98 for the upper face of the fingerj92 is provided with the bracket 34. The last mentioned arms95 and 91 are mounted to swing out of the way by contact with their respective fingers 8|, 82. seas-to permit these fingers to be aligned with their respective lug portions 93,94, in the event that stretch, expansion due Fig. 6, where it will be seen that upon rotation of the fingerstothe position shown in Fig. 3, the

fingers will strike their respective arms swinging them 'momentarily to'the left and then as reciprocatory motion is imparted to the rods '58 and 19, these arms will right themselves and resume their initial. position. as best seen infFig. 8.

Thereciprocatory, movement of the rods 78 and 19 being mparted t m abl 8. and 88 t on s i n. t 'tbel qll y. 921 1 1) oun on the shaft 99. The mutilated ratchet I is fixed to the shaft 99, and is positioned on the car shelf IOI in which the shaft 99 is journaled. The

' ratchet I00 is provided with a pin I02 protruding will assume a straightened. position in the cut.

away portion I00 in the ratchet I00 so the pulley 92 may be reversely rotatedfrom the position in Fig. 21 to its initial'position shown in Fig. 19, the

' dog I during this action being disposed oppopressed dog I21,

guide the shorter arms I I2, H3. 7 carries opposed spring pressed pawls, I23,'I24, each being respectively provided with downsitely to the position shown in Fig. 20. To prevent-unauthorized or inadvertent rotationof the shaft -99, a'safety dog I06 is adapted to engage against the shoulder I01 on the mutilated ratchet I00, (Fig. 19) this'dogbeing moved out of engagement with said shoulder (Fig. 20) upon initial rotation of the pulley 92 in the direction of the arrow, and thereafter the pin I02 may drive the ratchet through contact with the forward portion of the slot I03. 1

The movements of the slide brackets 83 and 84 are designed to impart to the shaft 99 rotation in one direction of about 300 and then counter-rotation of the same amount. This rotation of the shaft 99 is utilized to progressively rotate the transfer member I08 which comprises a central flattened ring portion I09, provided with transfer arms IIO, III, and shorter guide arms H2, H3.

The transfer member I03 is adapted to be rotated and then to be moved from the front to the back during the counter-rotation of the shaft 99.- The arms IIO, III

a tray II2 from the car to the receiving means and to slide a tray I I3 from the receiving means to the car.

Figs. 9, 10, 111, 12, 13, best illustrate one manner in whichthis maybe accomplished. A collar II4, fixed to the shaft 99, is'pro'vided at its lower end with a lug II 5 which is engageable with the transfer member at the flattened ring-like The transfer member is positioned tomove in a rotating freely mounted collar II9, which is hollowed for the flattened ringlike portion I09 and slotted at I2I to permit movement of the transfer arms H0 and III, and further slotted at I22 to This collar -I I9 reaching tail portions I25, I26. These tail portions may alternately be engaged by a spring a similar dog I28 being disposed in opposite relation to the dog I21. The collar 'II9 is provided with'the stop shoulders I29, I30;

I3I, I32, and is also provided with diametrically opposed: upstanding projections I33, I34. The last mentioned projections areultimately engageable by the tail H8 of the bail IIO to impart rotation to the collar II9 and so to the transfer member I08. r

The lower end of the shaft 93 has affixed there'- to a carsteadying and positioning cam I35 which .is adapted to protrude itself between the shelf I35 and the member I31, which is tensioned by :means such as the springs I38.

,The member 'I31is provided at each the shelf to'the car.

are adap e du their rotational movement, to respectively slide 40 with the index mark I4 I.

end adjacent tothe inner edge of the shelf I36, with upstanding lugs I31. When the member I31 is moved downwardly by the cam I35, the tops of these lugs are brought to a position below the top of the shelf and a tray may be slid from the car to the shelf and vice versa. When the member 5311s returned to the position shown-in Figs. 1 and 2, these-lugs serve to act against the chordal faces of the tray on the shelf to prevent'inadvertant displacement thereof,

As can be seen from the foregoing, counterclockwise rotation of the shaft 99 will bring the tail II'8 against the near face of the pawl I24 as best seen in Fig. 17 rocking it outwardly as seen in Fig. 18 so that its downreaching tail portion I26 will also rock the dog I21 outwardly and away fromthe shoulder I29. The leading face of the tail I I8 will now abut against the upstanding H9 and the transfer member I08. After 180 of rotation of that sleeve, the parts will assume the position shown in Fig. 13 with the dog I21 now engaging against the shoulder I3I the other dog I28 now having engagement with the shoul der I32. It will be noted that in this position the transfer member has been moved forward so that the tray II3 on the transfer shelf I36 may be properly positioned out of the path of any portion: of the car.' Now as the shaft 99 rotates clockwise, the lug II5 servesto retract or move back the transfer member to similarly align and position the tray which had been transferred from In this position the parts are again ready to be operated.

In the event of a plural number of transfer devices whichmay be simultaneously operated by common mechanism not in all casesvvill it be desirable to effect such a transfer. In that event,

the bail II6 of that transfer device which is'not to operate, isswung down so its tail II8 may be out of path of the members it is intended to operate against, and in this'wise no rotation is .imparted to that particular transfer member.

The ratchet I00 is provided so that the full cycle of operation of the transfer arms must be completed before the shaft 99 can be re-rotated in the clock-wise direction.

"So that the operator may be apprised of the position of the car in relation to a selected-upper level, there is provided at I39 a member provided with gradua'tions I40 each indicative of the posi-' tion of the car at a certain level and readable the shaftway, the rotationof the shaft 33 which carries a Worm I42 imparts to the gear sector I43, the slow rotation to the member I39 neces- As the car is raised in sary to bring one of the graduation marks I40'in' line with the indexed point I3I at the time the car is at a certain level.

When the apparatus is ready for operation, the car 22 is provided with a tray II2', each of the levels which are to receive a delivery are each provided with atray I I3. Assuming in this case, that bottled milk is to be delivered, the required number of bottlesare placed in cavities in the tray H2. The operator then turns the handle 21 to elevate the car and watches the graduations I40 until the proper one aligns with the. indexed point I4I. at the proper level. He then rotates the hand wheel 52 which first, by means of the cam notch 41 acting against the lug 46, rocks the bell'crank lever 43--45 so the projection 42 seeks the hole M in the drum 38. Continued'rotation of the hand wheel'ximparts through the medium of the shaft This indicates to him that the car is the car.

5| and the gearing '54, imparts rotation to the shaft 53. The enlargement of the shaft '53, through the medium of its notch 6| carries the pawl 60 in counterclock-wise direction. In this manner since the pawl 69 is carried by the gear 58 the rack I2,-'I3 moves toward the left (Fig. 5) to cause partial rotation of the rods I8 and 19.

When the pawl 60 has been moved a sufiicient amount to cause the rocking of these rods, its tail 62 engages against the fixed stop 64 to free the pawl from the driving action of the shaft 53 and thereafter for the continued rotation of that shaft the gear 58 remains stationary. Immediately after the rods are so partially rotated, the head 68 of the pawl 63 finds the notch H in the enlargement on the shaft 53 and rotation, because the pawl is carried by the gear 59, is imparted to that gear. This rotation oppositely reciprocates the racks' 'i'B and TI and the rods 18 and 19. The slides 83 and 8-4 respectively cooperative with the rods l8'and I9 are in this manner moved in opposite directions; that is, the slide 83 is moved upwardly, and the slide 84, downwardly (see Fig. 8).

Through the medium of the cables 88 and 89, the pulley 92 is therefore given a rotation in one direction somewhat less than 360. This rotation is imparted to the .shaft 99 through the medium of the pin I32 or the pulley and the slot I03 on the ratchet wheel attached to that shaft. The rotation of that shaft, in this case, counterclockwise, causes the tail H8 of the bail H6 to first raise the dog I27 away from its shoulder I29 and then to engage against the lug I33 to drive the collar I I9 in the said ceunterclock-wise direction. The arm III) will then engage against one of the chordal faces of the tray I I2 to slide it from its position in the car to the shelf I36 and the arm I I I will similarly engage one of the chordal faces of the tray H3 to slide it from the shelf I36 to Upon the completion of the half revolution in the oounterc1ockwise direction of the arms they will assume the position'shown in Fig. 1 3, the transfer of the trays having been effected.

To insure that no portion of the tray H2 protrudes into the path of the car, the oppositeor clock-wise direction of the shaft 99 now through the medium of the cam lug H5 slides the transfor member and its arms back to the position shown in Fig. 10, where it is'again ready for another cycle of operation. So the car 22 may be maintained in its proper relation to the selected level, the cam I35 protrudes itself between the bottom of the shelf I38 and the spring tensioned member E31, this also prevents movement of the car in the shaft, should the parts not be returned to their normal position after the transferring cycle. It will of course be apparent that opposite movement ef the hand-wheel after the transfer has been effected, is necessary to reset all the parts to their initial positions so they may be ready to again perform their functions.

It will be noted that the drum I 38 is so mounted with particular reference to the screw 39 so as to prevent the entran e of thelug 42 into the hole 41 at any time other than when the car is at one of the upper levels.- The screw serves to move the drum 38 endwise and therefore, moves the hole 4i out of alignment with the lug Mlwhen the car is in an iii-between position with relation to the upper levels.

While in this case only one upper level has ,beenillustrated, it is of course apparent that 'severalsuch levelsv may be provided andalso that at cachlevel several receiving traysmay be prointercliange one tray for engage and push against 2.

vided, the car of ooursebeing also provided with a similar number of transferring devices. -When the latter is the case, transferring'of the trays may be effected at the will of the operator by setting those of the bails H6 which relate to the particulartransfer devices he wishes to operate. It is also contemplated that doors individually entering on eachshelf adapted to be locked and opened only by authorized persons may be provided against possible theft of the delivered merchandise.

Arrangements may be made to apprise the persons making. delivery, the requirements of the tenant or, home owner. One method by which this may be accomplished, is illustrated in Fig. 2, and comprises a plurality of switch contacts I44 in electrical circuit with one side of tell-tale lamps I45 at the basement level. The other side of each of these lamps are preferably in circuit, through a switch I =36, with oneleg of the line current, the other leg of the line current being connected to an arm H'I adapted to be contacted with any one of the contacts I44. In this manner, the potential receiver or the merchandisc, as in this case bottles of milk, 'may set the arm ill on one of the contacts M4 to designate what his or her requirements may be and the person making delivery, upon pushing the switch .i'i 6,,may determine by which one or the lights illuminate, what those requirements are. Of

course, for a plurality of upper levels the arrangement would be similar for eachlevel.

Although I have described my improvements with considerable detail and with'respect to a certain particular form of my invention, I do not desire to be limited to such details since many changes and modifications in the form, arrangements, proportions, and sizes thereof, may well be made without departing from the spirit and scope of my invention in itsbroadest aspect.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is: V

1. In a dumb-waiter, a car movable from one level to another in the shaftway" thereof, means carried by said car and receptive of an article, means at each level to receive the carcarried means and means to transfer'said car carried means from thecar to the receiving means at each level selectively, said transfer means including a rotating member for eifecting a simultaneous transfer of the car-oarried means to the receiving means and from the receiving means to the car.

2. In a dumb-waiter, a car movable from one level toancther in theshaftway thereof, a movable substantially semi-circular tray having a chordal side, carriedby said car and receptive Of an article, a shelf at each level, a substantially semi-circular tray having a chordal side movably supported on the shelf and means to interchange one tray for the other.

able substantially semi-circular tray having a chordal side carried by said car and receptive of an article, a shelf at each level, a substantially semi-circular tray having a chordal side, movably supported on the shelf and means to the other, said means including substantially radial arms adapted to portion of the chordal side of each tray.

4. In a dumb-waiter, a car movable from one levelto. another in the shaftway thereof, a movable substantially semi-circular tray having a chordal side carried by said car and receptive of an article, a shelf at each level, a substantially semi-circular tray having a chordal side movably supported on the shelf andmeans to' interchange one tray for the other, said means including substantially radial arms adapted to first rotate in a semi-circular path to engage and push against a portion of the chordal side of 7 a pre-settable bail pivotally carried by the shaft,

acollar provided with diametrically opposed lugs and freely mounted on the shaft, dog means to retain the collar in one of two positions, means on the bail adapted when the shaft is rotated, to first act against the dog means to free the collar for rotation and then to engage one of the collar lugs to impart the rotation of the shaft to the collar, 2, transfer member mounted for rotation with the collar and arms on the transfer member engageable in the tray to effect a transfer thereof,

6. Means to transfer a tray from one support to another comprising a shaft, means to rotate the shaft first in one direction and then in the other, a pre-settable bail pivotally carried by the shaft, a collar provided with diametrically opposed lugs and freely mounted on the shaft, dog means to retain the collar in one of two positions, means on the bail adapted when the shaft is rotated in one direction, to first act against the dog means to free the collar for rotation and then to engage one of the collar lugs to impart the rotation of the shaft to the collar, a transfer member mounted for rotation with the collar, arms on the transfer member initially positioned at one side of the center of the shaft and engageable against the tray'to effect the arms assume a position to the other side of said shaft and means carried by the shaft to move the armsback to their initial position when the shaft is oppositely rotated. a

-'7. In a dumb-waiter having means to transfer a tray between the car'and an upper level, a tray supporting shelf at the level, a spring tensioned member underneath the shelf means to position a the car in proper relation to said shelf during the transferring cycle, said means comprising a member adapted to beintroduced between the shelf and the spring tensioned member.

8. In' a dumb-waiter having a shaftway provided with tray bearing shelves and a car pro-- vided with tray bearing means, means to interchange the'car carried tray withthe shelf carried tray at a selected level, means to effect the mentioned interchange, said means comprising means at the bottom of the shaft, and means carried by the car, the last'mentioned means being manually operable by a hand wheel associated with the means at the bottom of the shaft.

9. In a dumbwaiter, a car movable from one level to another in a shaftway. thereof, a shelf on each level, a substantially semi-circular tray the transfer thereof, at which time having a chordal side carried by said car, asimilar tray movably supported on each shelf, means on the car including rotating arms for simultaneously interchanging the car-carried tray selectively with any of the shelf-carried trays, means associated with each shelf normally to hold its tray against displacement, means on the car to withdraw said displacement-preventing means to allow for the interchange of the'trays when the car is at the selected level, said rotating arms being adapted to move forward after rotation to thrust the previously car-carried tray further onto the shelf and then tomove backward to thrust the previously shelf-carried trayfurther onto the car.

10. In a dumbwaiter, acar movable from one level to another in a shaftway thereof, a shelf on r each level, a substantially semi-circular tray having a chordal side carried by said car, a similar tray movably supported on each shelf, means on the car including rotating arms for simultaneously' interchanging the car-carried tray "selectivelywith any of the shelf-carried trays,

said rotating arms being adapted to rotate in a semi-circular path to engage and push against" a portion of the chordal side of each tray, and means adapted to move the" arms forward in a horizontalplane after rotation to thrust the previously car-carried tray further onto the shelf and then tomove backward to thrust the previously shelf-carried tray further onto the car.

11. In a dumbwaiter, a car movable from one level to another in a shaftway thereof, a shelf on each level, a substantially semi-circular tray having a chordal side carried by said car, a similar tray movably supported on each shelf, means on the car including rotating arms'for simultaneously interchanging the car-carried tray selectively with any of the shelf-carried trays, means associated with each shelf to normally hold its tray against displacement, means on the car to withdraw saiddisplacement-preventing means to allow for the interchange of the trays when the car is at theparticular level, said rotating arms being adapted to. rotate in a semi-circular path to engage and push against a portion of the chordal side of each tray, means adapted to move the arms forward in a horizontal plane after rotation. to thrust the previously car-carried tray further onto the shelf and then to move backward to thrust the previously shelf -carried tray further onto the car, and means to retract the withdrawing means when the interchange has been effected.

12. In a dumbwaiter having means to interchange similar trays between the car and an upper level, a tray supporting shelf at each level, a spring tensioned member underneath the shelf, upwardly extending lugs on said member normally to extend above the upper surface of the shelf to prevent displacement of the shelf-carried, tray, means to position the car in proper relation to such shelf during the interchanging cycle, said means comprising'a cam adapted to be introduced between the shelf and the spring tensioned mem- 

